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Chlorhexidine Allergy

Frequently Asked Questions

pdfASCIA PC Chlorhexidine allergy 2024136.89 KB 

This document has been developed by ASCIA, the peak professional body of clinical immunology/allergy specialists in Australia and New Zealand, in conjunction with ANZAAG, the Australian and New Zealand Anaesthetic Allergy Group. ASCIA information is based on published literature and expert review, is not influenced by commercial organisations and is not intended to replace medical advice. For patient or carer support contact Allergy & Anaphylaxis Australia or Allergy New Zealand.

Q 1: What is chlorhexidine?

Chlorhexidine is a highly effective antiseptic agent. Allergic reactions to chlorhexidine are rare, but are increasing in frequency, possibly due to increased use of chlorhexidine containing products. As antibiotic resistant bacteria are becoming more common, the use of chlorhexidine in both prevention and treatment of infection is likely to continue.

Chlorhexidine is used to reduce the risk of infection and is:

  • Routinely used in hospitals for handwashing and to clean the skin before performing a surgical procedure or inserting a needle.
  • Contained in some surgical dressings, medical devices (such as central venous lines) and lubricants.
  • Found in many over the counter (OTC) products.

See below for a list of some products that may contain chlorhexidine.

Q 2: If you are allergic to chlorhexidine, what do you need to be aware of?

As chlorhexidine can be hidden, for example, as a coating agent on medical devices such as central venous lines, allergic reactions can be difficult to diagnose. If you are allergic to chlorhexidine you need to be aware that:

  • The presence of chlorhexidine is often not obvious, and labelling can be inconsistent.
  • There is no universal symbol identifying that a product contains chlorhexidine.
  • It may be described using the full word ‘chlorhexidine’ or sometimes as an abbreviation such as ‘CHG’ in dressings or ‘AGB’ on central venous lines.

If you are uncertain, ask your pharmacist to help to ensure OTC preparations do not contain chlorhexidine.

People with chlorhexidine allergy often have more than one reaction due to misdiagnosis or accidental re-exposure caused by inadequate labelling or awareness. People with chlorhexidine allergy should be able to tolerate other antiseptic products due to the lack of cross-reactivity.

Q 3: Can chlorhexidine cause anaphylaxis?

Allergic reactions to chlorhexidine are rare but are increasing in frequency. Immediate allergic reactions are the most serious adverse reactions to chlorhexidine. In people with immediate allergy, contact with chlorhexidine results in symptoms including itching, hives (urticaria), and angioedema (swelling).

Anaphylaxis is the most severe type of allergic reaction and should always be treated as a medical emergency. Anaphylaxis requires immediate treatment with adrenaline (epinephrine), which is injected into the outer mid-thigh muscle. If treatment with adrenaline is delayed, this can result in fatal anaphylaxis.

Anaphylaxis to chlorhexidine usually occurs when it enters the body through an opening of the skin during a medical procedure. Chlorhexidine allergy is a well recognised cause of anaphylaxis during surgery. A history of other allergies, such as eczema, asthma, or allergic rhinitis (hay fever), does not appear to increase the risk of having chlorhexidine allergy.

Q 4: Can chlorhexidine cause dermatitis?

Chlorhexidine can cause irritant dermatitis. This is not a true allergic reaction as it does not involve a specific immune response. Irritant dermatitis is caused by chlorhexidine directly irritating skin and results in rough, dry, and scaly skin, sometimes with weeping sores.

Chlorhexidine can also cause allergic contact dermatitis. While the symptoms of allergic contact dermatitis look similar to those of irritant dermatitis, allergic contact dermatitis involves an immune response that usually occurs 12-48 hours after contact with chlorhexidine.

Dermatitis to chlorhexidine can cause discomfort but is not dangerous. Some people with allergic contact dermatitis may later have immediate allergic reactions to chlorhexidine. It is important to recognise, treat, and record these reactions if they happen and avoid future chlorhexidine exposure.

Q 5: How is chlorhexidine allergy diagnosed?

Your doctor will assess your clinical history to identify the cause of your allergy. This will often be followed by allergy testing to help confirm or exclude chlorhexidine allergy. Allergy skin tests and/or blood tests for allergen specific IgE are often used. Other types of skin tests called patch tests may be used for the diagnosis of allergic contact dermatitis.

Q 6: How is chlorhexidine allergy managed?

Management of chlorhexidine allergy involves careful avoidance of chlorhexidine.

  • Check labels carefully to make sure that chlorhexidine is not included in prescribed or OTC products.
  • Ask health care professionals such as pharmacists if you are not sure whether a product contains chlorhexidine.
  • Advise doctors, nurses, dentists, and blood collectors of your chlorhexidine allergy in advance of any procedures, dental treatments, blood tests or x-rays, to ensure that chlorhexidine is not used.

There is no evidence that chlorhexidine allergy may resolve with time or by avoidance. This means that a person with chlorhexidine allergy may need to avoid chlorhexidine lifelong.

  • If you have had anaphylaxis, consider carrying medical identification stating that you are allergic to chlorhexidine for use by medical professionals if you are unconscious or confused. This is important as chlorhexidine is often used as an antiseptic in medical procedures.
  • Discuss having an ASCIA Action Plan for Allergic Reactions or ASCIA Action Plan for Anaphylaxis with your doctor. An adrenaline injector such as EpiPen or Anapen may be prescribed by your doctor.

Q7: What products can contain chlorhexidine?

This list is not exhaustive.

Chlorhexidine in hospital settings

  • Skin antiseptic wipes and swabs
  • Hand gels and hand wash solutions
  • Surgical skin disinfectants
  • Pre-surgery wash sponges and wipes
  • Surface cleaning sprays and solutions
  • Lubricant preparations
  • Mouthwash
  • Central venous lines
  • Surgical dressings and mesh

Chlorhexidine in community settings

  • Hand gels and washes
  • Mouthwashes, toothpastes and other mouth products
  • Disinfectants or antiseptics
  • Shampoo, body wash, sponges and wipes
  • Skin creams, ointments and cleansers
  • Antiseptic throat lozenges and sprays
  • Nasal sprays
  • Cosmetics

New products containing chlorhexidine are frequently released, so it is essential for people with a confirmed chlorhexidine allergy to read all ingredient labels carefully before using a product.

 © ASCIA 2024

Content updated June 2024

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